It is generally known that textile floor coverings can be provided with a firmly adhering backing layer of polyurethane foams by applying a reactive liquid mixture of polyurethane-forming components to the back of the textile (see, e.g. German Offenlegungsschriften Nos. 2,208,995; 1,926,285 and 2,262,742). In the one prior art process, a reactive liquid foamable mixture of polyisocyanates and polyols is applied to the back of a textile floor covering to form a thin coating of a flexible polyurethane foam which, before hardening, has a second layer of a preformed flexible polyurethane foam applied to it (see, e.g. German Offenlegungsschrift No. 2,262,742).
Unfortunately, many conventional processes are attended by significant disadvantages in addition to which the products obtained therefrom are of inadequate quality. In particular, the fixing of the nap and filaments of the textile floor covering is generally inadequate when foamed coatings are applied. In addition, the product is generally not "stiff" enough for the consumer.
To offset these disadvantages, the prior art has attempted to initially preconsolidate the textile substrate with a first coat which itself has high strength and, upon completion of preconsolidation, to apply the reactive foamable layer in a second operation. The art has also attempted to join a preformed foam layer to the textile floor covering by a thick coat of adhesive which is also intended to fix the nap. Unfortunately, this is both complicated and expensive because different starting components have to be used and because additional process steps are involved. In fact, because of its foam structure, the layer of adhesive is of only limited strength, with the result that, in many cases, the anchorage of the textile filaments is as inadequate as when the foamed covering is directly produced on the back of the textile.